1. Field of the Invention
The field of the invention is support cushions for the back; more particularly, the field pertains to cushions for supporting the thoracic and lumbar regions of the back when the user is in the sitting position.
2. Prior Art
Cushions for providing support to the lumbar region of the back are relatively well-known. Examples of these can be found in some modern cars. The front seats in these cars now include a raised forward contour towards the bottom of the seat back. This raised portion pushes forward on the lumbar region of the user's back as the user leans back against it. Additionally, there are some variations of portable lumbar support cushions that are sold through medical supply houses and pharmacies that provide similar support for the lumbar region and may be employed in car seats and chairs that would not otherwise provide lumbar support. These lumbar support cushions provide a certain degree of support for the user's lumbar region. These prior art back support cushions and car seats may be in the form of tubular rolls; sometimes include a curved contour in the region of the users loins; and, some have moveable supports. The support provided by these prior art cushions, however, is limited to the sagittal, i.e., forward/ backward plane in the case of the tubular rolls and those with moveable supports, and also in the horizontal plane in the case of those that include a curved contour in the region of the loins.
While the lumbar support cushions and contoured car seats provide a certain degree of support for the lumbar spine and the loin area, they are not, nor are any other known cushions also designed with a particular surface plane geometry that provides in combination: multiple differential neurosensory, proprioceptive and kinesthetic cues to the muscular, joint and bony elements of the back; a relief zone for the spinous processes of the vertebrae of the lumbar and thoracic portions of the spine; support and kinesthetic cues to the area immediately caudal and at the apex of the thoracic curve of the spine. Rather, the prior art cushions simply follow the major contours of the curves of the spine.